Star-shaped molecule of (Mn4O6)-O-II core with an S-t=10 high-spin state. A theoretical and experimental study with XPS, XMCD, and other magnetic methods

We report a comprehensive study of the electronic and magnetic properties of a star-shaped molecule comprising a (Mn4O6)-O-II core. One feature of this compound is weak magnetic coupling constants compared to other similar polyoxo compounds. This leads to complicated low-lying magnetic states in which the ground state is not well separated from the upper-lying states, yielding a high-spin molecule with a giant magnetic moment of up to 20 mu(B)/formula unit. We apply X-ray diffraction and magnetometry as well as other X-ray spectroscopic techniques, namely, X-ray photoelectron spectroscopy, X-ray magnetic circular dichroism, and X-ray emission spectroscopy. We compare our experimental results with ab initio electronic band structure calculations as well as the localized electronic structure around the Mn2+ ions with charge-transfer multiplet calculations.